package com.cqust;
import java.sql.*;
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;
/**
statement.setString(1,username);传值这里传值会做类型检查比较安全
statement.setString(2,userpwd);传值
1,2分别指的是第一个,第二个?
*/
public class JDBCTest06 {
public static void main(String[] args) throws Exception {
//初始化界面,返回用户输入的信息,使用map集合存储
Map<String,String> userInfo = initLogin();
//登录方法,返回值是布尔类型
Boolean loginInfo = login(userInfo);
System.out.println(loginInfo ? "登录成功":"登录失败");
} /** * 用户登录界面 * @return 返回用户的信息,存在集合中 */ public static Map<String,String> initLogin(){ Map<String,String> userInfo = new HashMap<>(); System.out.print("请输入你的用户名:"); Scanner scanner = new Scanner(System.in); String username = scanner.next(); System.out.print("请输入你的密码:"); String userpwd = scanner.next(); userInfo.put("username",username); userInfo.put("userpwd",userpwd); return userInfo; } /** * 使用jdbc技术完成登录检测 * @param map 用户的信息存储在集合map中 * @return 最后返回登录成功还是失败 * @throws Exception 这里为了省点劲直接throws */ public static boolean login(Map<String,String> map) throws Exception{ String username = map.get("username"); String userpwd = map.get("userpwd"); boolean loginInfo = false; //1.注册驱动 Class.forName("com.mysql.jdbc.Driver"); //2.获取连接 Connection connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/cqust_db", "root","hch1"); //3.获取数据库操作对象,预编译sql String sql = "select username,userpwd from t_user_login where username = ? and userpwd = ?"; PreparedStatement statement = connection.prepareStatement(sql); statement.setString(1,username); statement.setString(2,userpwd); //4.执行sql //String sql = "select username,userpwd from t_user_login where username = '"+username+"' and userpwd = '"+userpwd+"'"; ResultSet resultSet = statement.executeQuery(); //5.这里只需要看是否有数据,如果查询到数据,则登录成功,直接loginInfo = true; if (resultSet.next()){ loginInfo = true; } //6.关闭资源 if (resultSet!=null){ resultSet.close(); } if (statement!=null){ statement.close(); } if (connection!=null){ connection.close(); } return loginInfo; }
}